Thin-film transistors (TFTs) are a class of field-effect transistors (FETs) in which the channel material is a deposited thin film rather than a monocrystalline material. A common application of TFT technology is liquid crystal displays (LCD), but they are also advantageous in other applications as the thin film deposition processes employed in TFT fabrication are relatively low (e.g., below 450° C.). TFTs can be made using a wide variety of semiconductor materials, such as silicon, germanium, silicon-germanium, as well as various oxide semiconductors (also known as semiconducting oxides) including metal oxides like indium gallium zinc oxide (IGZO).
In some examples, in a TFT, due to scaling of gate length Lg, control of a gate stack over a short cannel may reduce. It may be useful to overcome such short channel effects.